1. Field of the Invention
This invention relates to a new weft brake for shuttleless looms which, being self-cleaning and hence formed so as to prevent the inevitable dust and fluff produced by the weft being able to alter the set braking values, not only enables weaving to take place at a higher speed and hence with a considerable increase in productivity, but also enables better quality products to be obtained.
2. Discussion of the Background
As is well known in shuttleless loom weaving, the weft yarn provided by a feed bobbin does not always travel at a constant speed, but is subjected to acceleration and deceleration during each insertion cycle, thus requiring the use of a weft brake which allows the yarn to travel freely without braking during acceleration, but suitably brakes it during the other stages. Different types of weft brakes are already known in the state of the art, including one with electromagnetically adjusted braking action, in which the weft yarn is passed between a horizontal elastic blade, made at least partly of ferromagnetic material, and an underlying flat support plate of non-magnetic material, against which said elastic blade is suitably pressed by the attraction of at least one electromagnet of adjustable excitation.
All said known weft brakes have however the drawback of not being self-cleaning so that the yarn-generated dust and fluff which accumulate progressively between the braking members, together with the flocks of fluff which randomly come into contact with the weft yarn and are carried thereby between said braking members, create braking malfunctioning to the point of also causing stoppage of the loom and also make it necessary to manually clean the weft brake before restarting the loom.